1. Field of the Invention
The invention concerns a dosing device for introducing germicide or disinfectant into a water-supplied supply device for making aseptic or disinfected water available to users.
2. Description of the Related Art
It is generally known to disinfect water by addition of certain chemical substances. In these cases it is conventional to add germicides or disinfectants in tablet form or, in larger amounts, as solutions to the water to be disinfected in order to achieve a better mixing of the water to be disinfected. Independent of the type of addition, for the desired germicidal or disinfecting action attention must be given to make sure that a good mixing of the water with the germicide or disinfectant occurs.
A common environment of use is in the disinfecting of water needed by patients for dental hygiene in dental practices, for example for rinsing out the mouth.
Conventionally, dosing devices are employed for this, with which the water is periodically injected or inoculated. This means that the disinfectant is added at regular periods, since this device largely works on the basis of clocked magnets, which are associated with the pumps and/or valves employed therefor.
These types of components allow only large switch intervals, so that the intervals between the individual injections are correspondingly large. This results in substantial fluctuations in the concentration of the disinfectant in the water.
A further known device includes a supply container for disinfectant charged with compressed air, which is connected with a receiver via an appropriate pipe or hose conduit. In this delivery path a remote operable inlet valve for the disinfectant is provided, which controls the introduction of the disinfectant into the flow path of the water which goes to the receiver. Upon activation of the receiver this supply valve opens and in inactive times it is closed.
A particularly high volume concept of the water is not envisioned in this device. The mixing in of the disinfectant occurs with the help of a periodic magnet valve, of which the opening occurs periodically cyclically, as soon as the dispenser, for example pouring water into a glass for rinsing the mouth, is switched on, that is, as upon activation of the outflow. Here also fluctuations on concentration are unavoidable.
Finally there is known from DE 34 03 640 A1 a dosing device, which is the starting point of the present invention. In this device the disinfectant is introduced into the water in a special mixing chamber, which is incorporated in the supply conduit. The pressure conduit of a disinfectant conveying piston pump discharges into this mixing chamber.
For the purposes of dosing a control device is provided, which acts upon the piston pump in correspondence to the flow amount or, as the case may be, the flow velocity in the supply conduit, so that the desired amount of disinfectant is conveyed out of the supply container. The control of the piston pump can be achieved either by the rotation count of the drive motor or the transmission relationship of the reduction gear mechanism, in order to appropriately adapt the pressure stroke of the pump.
It has been found to be a disadvantage herein that the disinfecting action of the germicide is substantially limited in range to the mixing chamber itself. With longer periods of inactivity, as are conventional in the dental practice for example during two sequential days of the weekend, there exits the danger that the disinfecting action is reduced and impermissibly high contamination values occur. Further there occurs the problem, that in the course of the normal useage dead bacteria and other organic substances adhere as the so-called bio-film in the area of the supply conduit and in the downstream water conveying paths, which is an ideal nutrient supply for further germ growth. It is thus necessary to undertake a complete sterilization (basic- or intensive disinfecting) at regular intervals.
To do this the device must be taken out of commission. Thereafter the various hose connections must be released and there follows the connection to a separate pump system, which is specially provided for the complete disinfecting and the treatment with a 100% concentration of disinfectant introduced with the objective of removing the bio-film and sanitizing the water supply elements. Thereafter the conduit system must be rinsed with clean water, in order to avoid a subsequent unacceptably high concentration of disinfectant at the resumption of operation. A cleansing process of this type is time and cost consuming.
Further, the construction cost for this type of device is substantial, since besides the mixing chamber to be employed in the supply line, the piston pump in particular inclusive of its controls is relatively complicated. Besides the necessity to influence the rotation and/or the transmission relationship of the drive there must be provided special precautions in the form of over-pressurization valves and return conduits, in order to assure functional safety.
Finally, there occurs also in this device the undesirable fluctuations in concentration of germicide in the water, since the piston pump cyclically introduces the germicide corresponding to the stroke volume of the piston pump.
Beginning with this state of the art it is the task of the invention to provide a dosing device of the above-described type, which is simple in construction and easy to operate and which insures an addition of germicide corresponding to the requirements.